(a) Field of the Invention
The present invention relates to a self-assembled conjugate of a host molecule containing compound and a guest molecule containing compound, a delivery composition of a bioactive material comprising the self-assembled conjugate and a bioactive material to be delivered, and a composition for tissue engineering containing the self-assembled conjugate and a cell.
(b) Description of the Related Art
Extracellular matrix (ECM) plays a crucial role in defining the 3D environment of cells. Recently, synthetic hydrogels have emerged as highly promising materials to reconstitute artificial 3D environments that mimic the ECM for both in vitro and in vivo tissue engineering applications. A crucial challenge for such hydrogels is the facile formation and modular modification of the hydrogels in the presence of cells to ensure that cells are exposed to the proper cues for cellular development and differentiation at the right place and time. Strategies for the hydrogel formation and modification generally require highly reactive chemicals, noncovalent interactions such as ionic interactions and hydrogen bonding, and/or external stimuli such as light and temperature or pH change. However, most of these interactions are, up to date, neither controllable nor sufficiently stable in the body, causing a significant cytotoxicity in some cases.
On the other hand, supramolecular hydrogels have been developed using natural host-guest (receptor-ligand) pairs like (strep)avidin-biotin [(S)Av-Bt] with an extremely high binding affinity (K˜1013 to 1015 M−1), but their efficient exploitation has been hampered by the difficulties in chemical modification and mass production as well as the unknown immunogenicity of (S)Av. Alternatively, hydrogels based on synthetic host-guest pairs, such as α-cyclodextrin-polyethyleneglycol (α-CD-PEG) and β-CD-adamantane (β-CD-Ad), have been developed, which have an intrinsic limitation for in vivo applications due to the low binding affinity of CDs to their guests (α-CD-PEG, K˜102 M−1 and β-CD-Ad, K˜105 M−1).
Therefore, it has been required to develop materials for the facile formation and modular modification of the hydrogels having low cytotoxicity and low immunogenicity, which are suitable to cell therapy and tissue engineering applications.